The study discovered bacteria associated with sewage in sea-spray aerosols at Imperial Beach, according to a report in the San Diego Union-Tribune.
“Once pollutants become airborne that just means so many more people can be exposed to those pollutants,” said Kim Prather, the principal investigator on the study and director of the Center for Aerosol Impacts on Chemistry of the Environment at Scripps. “It extends well beyond just people going to the beach or getting in the water.”
The researchers have cautioned that the potential health consequences remain uncertain. Further studies are in progress, and they may involve an epidemiological inquiry.
The team, led by Prather, intends to swab surfers, lifeguards, and other individuals to assess the degree of respiratory exposure. In addition, they aim to analyze hospital records and track indoor air quality.
“The bottom line is we don’t know what the effect is yet of inhaling this cocktail that comes out of the ocean,” she said, adding: “This is tip of the iceberg. We’re trying to keep everybody calm.”
In early 2019 in the aftermath of some heavy rain, the study was launched. Researchers began by gathering air and water samples at the Tijuana River, Imperial Beach Pier, and Scripps Pier in La Jolla. Through DNA sequencing, the team was able to associate up to 76% of the airborne bacteria in Imperial Beach with the river, which was heavily polluted, the outlet reported.
According to Robert Knight, a co-author of the study and a professor of pediatrics, computer science, and engineering at UC San Diego, there is a significant body of research indicating the movement of microorganisms from the ocean to the atmosphere. However, this is the first study to directly connect airborne bacteria to a confirmed source of sewage, the Union-Tribune noted further.
“It was a complete shock to find how much of microbes in the air were traceable back to sewage,” he told the outlet. “We had no idea that effect would be so strong. Now that we know this is a real phenomenon,” he added, “we need to find out what are the impacts to human health.”
Swimming in water containing sewage can pose serious health risks. Sewage contains a variety of harmful pathogens, including bacteria, viruses, and parasites, that can cause a range of illnesses. Exposure to these pathogens can lead to gastrointestinal problems, skin infections, respiratory issues, and other health problems. In addition, sewage can contain toxic chemicals and heavy metals that can be harmful to human health.
Swimming in contaminated water can also increase the risk of infections in wounds, cuts, and other open sores. It is important to avoid swimming in water containing sewage and to always follow any warning signs or advisories issued by local authorities.
Officials have reported that Rep. Scott Peters has secured approximately $1.5 million in this year's omnibus spending bill to enable Prather and her team to conduct further research into the health effects of airborne pollutants and potential pathogens, said the paper.
In 2022, sewage pollution originating from Mexico led to the closure of beaches as far north as Coronado at an unprecedented rate. Imperial Beach, for instance, displayed signs alerting visitors of sewage contamination for 249 days last year. The Tijuana Sloughs, a well-known surfing spot located at the river's mouth, has been closed since December 2021, the outlet noted.